Disposable absorbent articles being adaptable to wearer&#39;s anatomy

ABSTRACT

Absorbent articles having a liquid permeable topsheet, a liquid impermeable backsheet, and an absorbent core disposed between said topsheet and said backsheet are disclosed. The backsheet has a physical variation along at least one axis, wherein said physical variation defines a first backsheet zone and a second backsheet zone, and at least one elastomeric element having at least one primary direction of stretch, said elastomeric element at least partially overlapping and joined to first and/or second backsheet zone, wherein a relaxed pathlength of said elastomeric element in the primary direction of stretch is less than a total pathlength of said backsheet in the region of overlap. The physical variation is a measurable difference as measured by a physical property selected from the group consisting of basis weight, thickness and density.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of, and claims priority under 35U.S.C. §120 to, U.S. patent application Ser. No. 12/879,309, filed onSep. 10, 2010, which is a divisional of U.S. application Ser. No.10/811,696 filed on Mar. 29, 2004, the entire disclosures of which arehereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a disposable absorbent article havingstretchable properties for sustained fit and conformity to the wearer'sanatomy while also being adaptable to the varying three-dimensionalnature of the wearer's anatomy.

BACKGROUND OF THE INVENTION

The major function of absorbent articles, such as disposable diapers andadult incontinent briefs, is to absorb and contain body exudates. Onecommon mode of failure for such products occurs when body exudates leakout of the gaps between the article and the wearer's leg and/or waist toadjacent clothing because they are not immediately absorbed within thearticle. As such, contemporary absorbent articles typically containstretchable materials in the waist, side and cuff regions to providesustained fit and a good seal of the article to the wearer's body.

One known technique for providing such stretchable materials is theincorporation of strands, films or nonwoven fibrous webs made ofelastomeric materials. Typically, such materials are stretchable in atleast one, and possibly multiple, directions. However, because the filmsor webs are made entirely of elastomeric materials, they are relativelyexpensive. Furthermore, these materials tend to have more drag on skinsurface, resulting in discomfort to the wearer of the article. In someselected approaches, these stretchable strands or films are laminated toone or more substrate layers, such as nonwoven webs, plastic films, ornonwoven/film composites. Since these substrates typically are made ofthermoplastic materials, they have very limited stretchability and arerelatively stiff. Consequently, these laminated structures provideconsiderable resistance to stretch and/or conformity to a wearer'sgeometry. This conformity deficiency is compounded by the uniformity ofthese laminates, thus making them unable to adapt to the varyingthree-dimensional nature of the wearer's anatomy.

Another known technique for providing such stretchable materials is theincorporation of stretch-bonded laminates and neck-bonded laminates.Stretch-bonded laminates are made by stretching an elastic strand in themachine direction (MD), laminating it to a nonwoven substrate while itis in the stretched state, and releasing the applied tension so that thenonwoven gathers and takes on a puckered shape. Whereas, neck-bondedlaminates are made by first stretching the nonwoven substrate in themachine direction such that it necks (i.e., reduces its cross direction(CD) dimension), then bonding CD oriented elastic strands to thesubstrate while the substrate is still in the stretched, necked state.Thus, the neck-bonded laminate will be stretchable in the CD, at leastup to the original width of the nonwoven before it was necked. In someselected approaches, a combination of stretch-bonding and neck-bondingtechniques are used to deliver stretch in both MD and CD directions. Inthis combined approach, at least one of the components is in a tensioned(i.e., stretched) state when the components of the laminates are joinedtogether. While this combined approach provides multi-directionalstretchability, the uniformity of these combined laminates is unable toadapt to the varying three-dimensional nature of the wearer's anatomy.

Yet another known technique for providing such stretchable materials isthe incorporation of zero strain stretch laminates. Zero strain stretchlaminates are made by bonding an elastomer to a nonwoven while both arein an unstrained state. These laminates are then incrementally stretchedto impart the stretch properties. These incrementally stretchedlaminates are stretchable only to the extent afforded by thenon-recovered (i.e., residual) extensibility of the laminate. Forexample, U.S. Pat. No. 5,156,793 discloses a method for incrementallystretching an elastomer-nonwoven laminate, in a non-uniform manner, toimpart elasticity to the resulting laminate. While this approach mayprovide non-uniform stretchability, this non-selectable stretch does notadequately adapt to the varying three-dimensional nature of the wearer'sanatomy.

What is needed is an absorbent article having stretchable properties forsustained fit and conformity to the wearer's anatomy while also beingadaptable to the varying three-dimensional nature of the wearer'sanatomy. More specifically, said absorbent article should be properlyshaped and/or sized to the wearer for better fit, comfort, and wearerappearance, yet have the ability to maintain the required tension whenon a wearer to achieve sustained fit and prevent sagging and/or droopingof the article. For example, said absorbent article should providebetter shaping (i.e., contouring) of the buttocks and/or waist region.In the case of a diaper, better fit and comfort can also impart betterfunctional performance such as reduced leakage since the diaper wouldbetter conform to the shape of a wearer.

SUMMARY OF THE INVENTION

A unitary disposable absorbent article comprising an absorbent corehaving a garment-facing surface and a body-facing surface, a liquidpermeable topsheet positioned adjacent said body-facing surface of saidabsorbent core, a liquid impermeable backsheet positioned adjacent saidgarment-facing surface of said absorbent core, said backsheet having aphysical variation in at least the central region of the backsheet alongand overlapping at least the longitudinal axis, wherein said physicalvariation defines a first backsheet zone and a second backsheet zone,and at least one elastomeric element having at least one primarydirection of stretch, said elastomeric element at least partiallyoverlapping and joined to said second backsheet zone, wherein a relaxedpathlength of said elastomeric element in the primary direction ofstretch is less than a total pathlength of said backsheet in the regionof overlap. The physical variation is a measurable difference asmeasured by a physical property selected from the group consisting ofbasis weight, thickness and density. The physical variation is such thatsaid second backsheet zone has a lower value than said first backsheetzone.

The absorbent article further comprises a front waist region, a backwaist region, a crotch region and, optionally, a buttocks region. Thebacksheet zones may be positioned in one or more of said regions. Theabsorbent article may further comprise a third backsheet zone which maybe positioned in one or more regions. The absorbent article may furthercomprise a second elastomeric element which may be positioned in one ormore backsheet zones. The first and/or second elastomeric elements maybe linear or non-linear (e.g., substantially u-shaped, etc.).

The absorbent article may be a disposable diaper (e.g., pant,non-preformed diaper), catamenial, adult incontinence product, or anyother like product.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims pointing out anddistinctly claiming the present invention, it is believed the same willbe better understood by the following drawings taken in conjunction withthe accompanying specification wherein like components are given thesame reference number.

FIG. 1 is a plan view of an exemplary, non-limiting general embodimentof a diaper in accordance with the invention;

FIG. 2 is a plan view of an exemplary, non-limiting embodiment of adiaper in accordance with the invention;

FIG. 3 is a plan view of another exemplary, non-limiting embodiment of adiaper in accordance with the invention;

FIG. 4 is a plan view of yet another exemplary, non-limiting embodimentof a diaper in accordance with the invention;

FIG. 5 is a plan view of yet another exemplary, non-limiting embodimentof a diaper in accordance with the invention;

FIG. 6 is a plan view of yet another exemplary, non-limiting embodimentof a diaper in accordance with the invention;

FIG. 7 is a plan view of yet another exemplary, non-limiting embodimentof a diaper in accordance with the invention;

FIG. 8 is a plan view of an exemplary, non-limiting general embodimentof a pant in accordance with the invention;

FIG. 9 is a plan view of the exemplary, non-limiting embodiment fromFIG. 7;

FIG. 10 a is a schematic, cross-sectional view of the exemplary,non-limiting embodiment from FIG. 9 being worn as illustrated along line10-10 in FIG. 11;

FIG. 10 b is a schematic, cross-sectional view of the exemplary,non-limiting embodiment from FIG. 8 being worn as illustrated along line10-10 in FIG. 11;

FIG. 11 is a side elevational view of the exemplary, non-limitingembodiment diaper from FIG. 2 being worn by a wearer; and

FIG. 12 is a schematic, side elevational view of the diaper in FIG. 11.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the following terms have the following meanings: Theterm “disposable” is used herein to describe absorbent articles thatgenerally are not intended to be laundered or otherwise restored orreused as an absorbent article (i.e., they are intended to be discardedafter a single use and, preferably, to be recycled, composted orotherwise disposed of in an environmentally compatible manner).

The term “disposed” is used to mean that an element(s) is formed (joinedand positioned) in a particular place or position as a unitary structurewith other elements or as a separate element joined to another element.

The term “joined” encompasses configurations whereby an element isdirectly secured to another element by affixing the element directly tothe other element, and configurations whereby an element is indirectlysecured to another element by affixing the element to intermediatemember(s) which in turn are affixed to the other element.

The term “unitary” absorbent article refers to absorbent articles whichare formed of separate parts united together to form a coordinatedentity so that they do not require separate manipulative parts like aseparate holder and liner.

The term “diaper” refers to an absorbent article generally worn byinfants and incontinent persons about the lower torso.

The term “stretch” means that a material has the ability to extendbeyond its original length in at least one dimension when subjected to atensile force (i.e., tension) applied in the direction of thatdimension. “Stretch” may be unidirectional, bi-directional, ormulti-directional. The specific “stretch” properties of a material mayvary along any of the stretch vectors. As used herein, stretch includesboth plastic and elastic deformation.

The terms “elastic” or “elasticity” mean that a material has the abilityto return to less than 120% of its original pre-stretched dimensionafter an elongation-relaxation cycle such as subjecting it to tension ora force in that dimension and then releasing the elongating tension onthe material (i.e., allowing the material to relax).

The term “elastic resistive force” describes an elastic force that tendsto resist an applied tensile force. Further, said elastic force causes amaterial to tend to contract to an untensioned configuration. Elasticresistive force may be conveniently measured according to the methodsdescribed in Edana: Tensile Strength 20.2-89, wherein the elasticresistive force is measured when the material sample is stretched to 25%elongation.

The term “longitudinal” refers to a direction running parallel to themaximum linear dimension of the article and includes directions within±45° of the longitudinal direction. The “lateral” or “transverse”direction is orthogonal to the longitudinal direction. The “Z-direction”is orthogonal to both the longitudinal and transverse directions. The“x-y plane” refers to the plane congruent with the longitudinal andtransverse directions.

The terms “water-permeable” and “water-impermeable” refer to thepenetrability of materials in the context of the intended usage ofdisposable absorbent articles. Specifically, the term “water-permeable”refers to a layer or a layered structure having pores, openings, and/orinterconnected void spaces that permit liquid water to pass through itsthickness in the absence of a forcing pressure. Conversely, the term“water-impermeable” refers to a layer or a layered structure through thethickness of which liquid water cannot pass in the absence of a forcingpressure. A layer or a layered structure that is water-impermeableaccording to this definition may be permeable to water vapor, i.e., maybe “vapor-permeable”. As is well known in the art, a common method formeasuring the permeability to water of the materials typically used inabsorbent articles is a hydrostatic pressure test, also called ahydrostatic head test or simply a “hydrohead” test. Suitable well knowncompendial methods for hydrohead testing are approved by INDA (formerlythe International Nonwovens and Disposables Association, now TheAssociation of the Nonwoven Fabrics Industry) and EDANA (EuropeanDisposables And Nonwovens Association).

The term “substrate” refers to any material, including a film, anapertured film, a nonwoven web, a woven web, a foam or a combinationthereof, or a cellulosic material including wood pulp, derivatized ormodified cellulosic materials, and the like, having a single layer ormultiple layers. The term “fibrous substrate” as used herein refers to amaterial comprised of a multiplicity of fibers that could be either anatural or synthetic material or any combination thereof, including, forexample, nonwoven materials, woven materials, knitted materials, and anycombinations thereof.

The term “nonwoven” refers to a fabric made from continuous filamentsand/or discontinuous fibers. Nonwoven fabrics include those made bycarding staple fibers, airlaying or wet laying staple fibers and viaextrusion processes such as spunbonding and melt blowing. The nonwovenfabric can comprise one or more nonwoven layers, wherein each layer caninclude continuous filaments or discontinuous fibers. Nonwovens can alsocomprise bi-component fibers, which can have shell/core, side-by-side,or other known fiber structures.

The term “pathlength” refers to a measurement along the topographicsurface of the region in question in a direction substantially parallelto an axis. For example, when characterizing a stretch zone, a relaxedpath length of the elastomeric element is measured and the totalpathlength (i.e., total surface length along the 2D gathered topographicpath) of the backsheet zone is measured. A method for determining thepathlength (i.e., surface-pathlength) of the respective regions can befound in the Test Methods section set forth in U.S. Pat. No. 5,916,663,entitled “Web materials exhibiting elastic-like behavior”, issued toChappell et al. on Jun. 29, 1999.

FIG. 1 is a plan view of an exemplary, non-limiting general embodimentof a diaper 20 of the present invention in its flat-out, uncontractedstate (i.e., without elastic induced contraction) with portions of thestructure being cut away to more clearly show the underlying structureof the diaper 20 and with the portion of the diaper 20 which contactsthe wearer shown facing the viewer. The diaper 20 includes alongitudinal axis 1000 and a lateral axis 1100. One end portion 36 ofthe diaper 20 is configured as a front waist region 36 of the diaper 20.The opposite end portion 38 is configured as a back waist region 38 ofthe diaper 20. An intermediate portion 37 of the diaper 20 is configuredas a crotch region 37, which extends longitudinally between the frontand back waist regions 36 and 38. The waist regions 36 and 38 generallycomprise those portions of the diaper 20 which, when worn, encircle thewaist of the wearer. The waist regions 36 and 38 may include elasticelements such that they gather about the waist of the wearer to provideimproved fit and containment. The crotch region 37 is that portion ofthe diaper 20 which, when the diaper 20 is worn, is generally positionedbetween the legs of the wearer. Another optional intermediate portion 39of the diaper 20 is configured as a buttocks region, which may belocated in or near the proximal end of back waist region 38 as shown, oralternatively may overlap the crotch region 37 and back waist region 38.The outer periphery of diaper 20 is defined by longitudinal edges 14 andend edges 10, 12 which are located along the front and back waist region36, 38, respectively.

The chassis 22 of the diaper 20 comprises the main body of the diaper20. The chassis 22 comprises an outer covering including a liquidpermeable topsheet 24 and/or a liquid impermeable backsheet 26 and atleast a portion of an absorbent core 28 encased between the topsheet 24and the backsheet 26. For unitary absorbent articles, the chassis 22comprises the main structure of the diaper with other features added toform the composite diaper structure. While the topsheet 24, thebacksheet 26, and the absorbent core 28 may be assembled in a variety ofwell-known configurations, preferred diaper configurations are describedgenerally in U.S. Pat. No. 3,860,003 entitled “Contractible SidePortions for Disposable Diaper” issued to Kenneth B. Buell on Jan. 14,1975; U.S. Pat. No. 5,151,092 issued to Buell on Sep. 9, 1992; and U.S.Pat. No. 5,221,274 issued to Buell on Jun. 22, 1993; and U.S. Pat. No.5,554,145 entitled “Absorbent Article With Multiple Zone StructuralElastic-Like Film Web Extensible Waist Feature” issued to Roe et al. onSep. 10, 1996; U.S. Pat. No. 5,569,234 entitled “Disposable Pull-OnPant” issued to Buell et al. on Oct. 29, 1996; U.S. Pat. No. 5,580,411entitled “Zero Scrap Method For Manufacturing Side Panels For AbsorbentArticles” issued to Nease, et al. on Dec. 3, 1996; and U.S. Pat. No.6,004,306 entitled “Absorbent Article With Multi-Directional ExtensibleSide Panels” issued to Robles et al. on Dec. 21, 1999; each of which isincorporated herein by reference.

The topsheet 24 may be fully or partially elasticized or may beforeshortened so as to provide a void space between the topsheet 24 andthe core 28. Exemplary structures including elasticized or foreshortenedtopsheets are described in more detail in U.S. Pat. No. 4,892,536 issuedto DesMarais et al. on Jan. 9, 1990 entitled “Absorbent Article HavingElastic Strands”; U.S. Pat. No. 4,990,147 issued to Freeland on Feb. 5,1991 entitled “Absorbent Article With Elastic Liner For Waste MaterialIsolation”; U.S. Pat. No. 5,037,416 issued to Allen et al. on Aug. 6,1991 entitled “Disposable Absorbent Article Having ElasticallyExtensible Topsheet”; and U.S. Pat. No. 5,269,775 issued to Freeland etal. on Dec. 14, 1993 entitled “Trisection Topsheets For DisposableAbsorbent Articles and Disposable Absorbent Articles Having SuchTrisection Topsheets”; each of which is incorporated by referenceherein.

The absorbent core 28 may comprise any absorbent material that isgenerally compressible, conformable, non-irritating to the wearer'sskin, and capable of absorbing and retaining liquids such as urine andother certain body exudates. The absorbent core 28 may comprise a widevariety of liquid-absorbent materials commonly used in disposablediapers and other absorbent articles such as comminuted wood pulp, whichis generally referred to as air felt. Examples of other suitableabsorbent materials include creped cellulose wadding; melt blownpolymers, including co-form; chemically stiffened, modified orcross-linked cellulosic fibers; tissue, including tissue wraps andtissue laminates; absorbent foams; absorbent sponges; superabsorbentpolymers; absorbent gelling materials; or any other known absorbentmaterial or combinations of materials.

Exemplary absorbent structures for use as the absorbent assemblies aredescribed in U.S. Pat. 4,610,678 entitled “High-Density AbsorbentStructures” issued to Weisman et al. on Sep. 9, 1986; U.S. Pat. No.4,673,402 entitled “Absorbent Articles With Dual-Layered Cores” issuedto Weisman et al. on Jun. 16, 1987; U.S. Pat. No. 4,834,735, entitled“High Density Absorbent Members Having Lower Density and Lower BasisWeight Acquisition Zones”, issued to Alemany et al. on May 30, 1989;U.S. Pat. No. 4,888,231 entitled “Absorbent Core Having A Dusting Layer”issued to Angstadt on Dec. 19, 1989; U.S. Pat. No. 5,137,537 entitled“Absorbent Structure Containing Individualized, Polycarboxylic AcidCrosslinked Wood Pulp Cellulose Fibers” which issued to Herron et al. onAug. 11, 1992; U.S. Pat. No. 5,147,345 entitled “High EfficiencyAbsorbent Articles For Incontinence Management” issued to Young et al.on Sep. 15, 1992; U.S. Pat. No. 5,342,338 entitled “Disposable AbsorbentArticle For Low-Viscosity Fecal Material” issued to Roe on Aug. 30,1994; U.S. Pat. No. 5,260,345 entitled “Absorbent Foam Materials ForAqueous Body Fluids and Absorbent Articles Containing Such Materials”issued to DesMarais et al. on Nov. 9, 1993; U.S. Pat. No. 5,387,207entitled “Thin-Until-Wet Absorbent Foam Materials For Aqueous BodyFluids And Process For Making Same” issued to Dyer et al. on Feb. 7,1995; U.S. Pat. No. 5,397,316 entitled “Slitted Absorbent Members ForAqueous Body Fluids Formed Of Expandable Absorbent Materials” issued toLaVon et al. on Mar. 14, 1995; and U.S. Pat. No. 5,625,222 entitled“Absorbent Foam Materials For Aqueous Fluids Made From high InternalPhase Emulsions Having Very High Water-To-Oil Ratios” issued toDesMarais et al. on Jul. 22, 1997. Each of these patents is incorporatedherein by reference.

The backsheet 26 is generally that portion of the diaper 20 positionedadjacent the garment-facing surface of the absorbent core 28. Backsheet26 prevents the exudates absorbed and contained therein from soilingarticles that may contact the diaper 20, such as bed sheets andundergarments. In preferred embodiments, the backsheet 26 issubstantially impermeable to liquids (e.g., urine) and comprises alaminate of a nonwoven and a thin plastic film such as a thermoplasticfilm having a thickness of about 0.012 mm (0.5 mil) to about 0.051 mm(2.0 mils). Suitable backsheet films include those manufactured byTredegar Industries Inc. of Terre Haute, IN and sold under the tradenames X15306, X10962, and X10964. Other suitable backsheet materials mayinclude breathable materials that permit vapors to escape from thediaper 20 while still preventing exudates from passing through thebacksheet 26. Exemplary breathable materials may include materials suchas woven webs, nonwoven webs, composite materials such as film-coatednonwoven webs, and microporous films such as manufactured by MitsuiToatsu Co., of Japan under the designation ESPOIR NO and by EXXONChemical Co., of Bay City, Tex., under the designation EXXAIRE. Suitablebreathable composite materials comprising polymer blends are availablefrom Clopay Corporation, Cincinnati, Ohio under the name HYTREL blendP18-3097. Such breathable composite materials are described in greaterdetail in PCT Application No. WO 95/16746, published on Jun. 22, 1995 inthe name of E. I. DuPont and copending U.S. patent application Ser. No.08/744,487, filed on Nov. 6, 1996 in the name of Curro. Other breathablebacksheets including nonwoven webs and apertured formed films aredescribed in U.S. Pat. No. 5,571,096 issued to Dobrin et al. on Nov. 5,1996. An exemplary, suitable backsheet is disclosed in U.S. Pat. No.6,107,537 entitled “Disposable absorbent articles providing a skincondition benefit” issued to Elder et al on Aug. 22, 2000. Othersuitable materials and/or manufacturing techniques may be used toprovide a suitable backsheet 26 including, but not limited to, surfacetreatments, particular film selections and processing, particularfilament selections and processing, etc. Each of these references ishereby incorporated by reference herein.

Backsheet 26 may also consist of more than one layer, as exampled inFIG. 1, wherein a backsheet outer layer 26 (often referred to as thebacksheet) may be made of a soft, non-woven material and a backsheetinner layer 27 may be made of a substantially impermeable film. Adhesive29, or any other suitable material or method, may be used to join layers26 and 27 together. One known method for attaching these materials is toapply adhesive in a continuous striped pattern, discontinuous stripedpattern or dot pattern. While a variety of backsheet configurations arecontemplated herein, it would be obvious to those skilled in the artthat various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention.

The diaper 20 may also include a fastening system 55. The fasteningsystem 55 preferably maintains the first waist region 36 and the secondwaist region 38 in a configuration so as to provide lateral tensionsabout the circumference of the diaper 20 to hold the diaper 20 on thewearer. The fastening system 55 preferably comprises a fastener such astape tabs, hook and loop fastening components, interlocking fastenerssuch as tabs & slots, buckles, buttons, snaps, and/or hermaphroditicfastening components, although any other known fastening means aregenerally acceptable. Some exemplary surface fastening systems aredisclosed in U.S. Pat. No. 3,848,594 entitled “Tape Fastening System forDisposable Diaper” issued to Buell on Nov. 19, 1974; U.S. Pat. No. B14,662,875 entitled “Absorbent Article” issued to Hirotsu et al. on May5, 1987; U.S. Pat. No. 4,846,815 entitled “Disposable Diaper Having AnImproved Fastening Device” issued to Scripps on Jul. 11, 1989; U.S. Pat.No. 4,894,060 entitled “Disposable Diaper With Improved Hook FastenerPortion” issued to Nestegard on Jan. 16, 1990; U.S. Pat. No. 4,946,527entitled “Pressure-Sensitive Adhesive Fastener And Method of MakingSame” issued to Battrell on Aug. 7, 1990; the herein before referencedU.S. Pat. No. 5,151,092 issued to Buell on Sep. 9, 1992; and U.S. Pat.No. 5,221,274 issued to Buell on Jun. 22, 1993. An exemplaryinterlocking fastening system is disclosed in co-pending U.S. Pat. No.6,432,098 entitled “Absorbent Article Fastening Device” in the names ofKline et al. issued on Aug. 13, 2002. The fastening system 55 may alsoprovide a means for holding the article in a disposal configuration asdisclosed in U.S. Pat. No. 4,963,140 issued to Robertson et al. on Oct.16, 1990. The fastening system may also include primary and secondaryfastening systems, as disclosed in U.S. Pat. No. 4,699,622 entitled“Disposable Diaper Having An Improved Side Closure” issued to Toussantet al. on Oct. 13, 1987. to reduce shifting of overlapped portions or toimprove fit as disclosed in U.S. Pat. No. 5,242,436 entitled “AbsorbentArticle With Fastening System Providing Dynamic Elasticized WaistbandFit” issued to Weil et al. on Sep. 7, 1993; U.S. Pat. No. 5,499,978entitled “Absorbent Article With Dynamic Elastic Waist Feature Having APredisposed Resilient Flexural Hinge” issued to Buell et al. on Mar. 19,1996; U.S. Pat. No. 5,507,736 entitled “Absorbent Article With DynamicElastic Waist Feature Comprising An Expansive Tummy Panel” issued toClear et al. on Apr. 16, 1996; U.S. Pat. No. 5,591,152 entitled“Absorbent Article With Dynamic Elastic Waist Feature Having APredisposed Resilient Flexural Hinge” issued to Buell et al. on Jan. 7,1997. Each of these patents and the co-pending application areincorporated herein by reference.

In alternative embodiments, the article may be preformed by themanufacturer to create a pant. The term “pant”, as used herein, refersto disposable garments having a waist opening and leg openings designedfor infant or adult wearers. A pant may be placed in position on thewearer by inserting the wearer's legs into the leg openings and slidingthe pant into position about the wearer's lower torso. A pant may bepreformed by any suitable technique including, but not limited to,joining together portions of the article using refastenable and/ornon-refastenable bonds (e.g., seam, weld, adhesive, cohesive bond,fastener, etc.). A pant may be preformed anywhere along thecircumference of the article (e.g., side fastened, front waistfastened). While the term “pant” is used herein, pants are also commonlyreferred to as “closed diapers”, “prefastened diapers”, “pull-ondiapers”, “training pants” and “diaper-pants”. Suitable pants aredisclosed in U.S. Pat. No. 5,246,433, issued to Hasse, et al. on Sep.21, 1993; U.S. Pat. No. 5,569,234, issued to Buell et al. on Oct. 29,1996; U.S. Pat. No. 6,120,487, issued to Ashton on Sep. 19, 2000; U.S.Pat. No. 6,120,489, issued to Johnson et al. on Sep. 19, 2000; U.S. Pat.No. 4,940,464, issued to Van Gompel et al. on Jul. 10, 1990; U.S. Pat.No. 5,092,861, issued to Nomura et al. on Mar. 3, 1992; U.S. patentapplication Ser. No. 10/171,249, entitled “Highly Flexible And LowDeformation Fastening Device”, filed on Jun. 13, 2002; U.S. Pat. No.5,897,545, issued to Kline et al. on Apr. 27, 1999; U.S. Pat. No.5,957,908, issued to Kline et al on Sep. 28, 1999, the disclosure ofeach of which is incorporated herein by reference.

Diaper 20 may also include such other features as are known in the artincluding cuffs, front and rear ear panels, waist cap features, a belt,elastics and the like to provide better fit, containment and aestheticcharacteristics. Such additional features are well known in the art andare described in U.S. Pat. Nos. 3,860,003; and 5,151,092, which areincorporated by reference herein.

Diaper 20 is preferably applied to a wearer by positioning one of thewaist regions under the wearer's back and drawing the remainder of thediaper between the wearer's legs so that the other waist region ispositioned across the front of the wearer. The fastening elements 55 arethen used by the caregiver to join the front and rear waist regions soas to encircle the wearer's waist. The elasticized side panels willtypically be extended and tensioned during this operation so as toconform to the size and shape of the wearer.

FIG. 2 is a plan view of an exemplary, non-limiting embodiment of adiaper 120 of the present invention in its flat-out, uncontracted state(i.e., without elastic induced contraction) with the backsheet 126,which contacts the wearer's garment, shown facing the viewer. Backsheet126 has at least two backsheet zones differing from each other in atleast one of the following physical properties: basis weight, thickness,and density. For example, a second backsheet zone 170 has a lower valueof one of said physical properties than does a first backsheet zone 160.Moreover, the ratio of said property in the second backsheet zone 170 tothe value of the same property in the first backsheet zone 160 is lessthan about 0.8, more preferably less than about 0.7, and most preferablyless than about 0.6. Typically, the ratio of the property in the secondbacksheet zone 170 to that in the first backsheet zone 160 is in therange of about 0.5 and about 0.8. Importantly, the physicalproperty(ies) of the backsheet are measured when the backsheet is in aflat-out, extended state (i.e., not in a pleated, folded, wrinkled, orelastically gathered state) and carefully removed from the remainder ofthe article. In so doing, care must be taken not to destroy the sampleor cause unintended gross deformation of any parts of the sample. Thelayers of the sample may be frozen to aid their separation from adjacentlayers of the sample, when necessary. Freezing may be accomplished usingPH100-15 circuit refrigerant made by Philips ECG, Inc. of Waltham, Mass.The average basis weight of a backsheet zone may be measured by weighinga known area of the backsheet zone and subsequently dividing the weightby the measured area. Alternatively, a sample cutting die may be used toensure proper, consistent and predefined sample sizes. In so doing, thedie cut may be made on one or more layers of the article so long as thebacksheet is ultimately removed from the other layers. In this way, anysubsequent deformation of the backsheet material prior to weighing isunimportant as the basis weight of the original sample is equal to thesample weight divided by the area of the predefined cut area (i.e.,original sample size). Lastly, and hereinafter applicable, said physicalproperties may be calculated as an average of multiple measurements,when appropriate. The backsheet zones of the present invention describedherein are preferably located primarily in the central portion of thediaper, overlapping the longitudinal axis of the diaper.

A lower basis weight, thickness or density of the second backsheet zone170 may be achieved by any known suitable techniques including, but notlimited to, partial plastic deformation (e.g., stretching) of saidsecond backsheet zone in at least one of a length and width dimension.For example, said stretching may be performed by a process commonlyreferred to as ring-rolling, as described in U.S. Pat. No. 5,167,897,entitled “Method for incrementally stretching a zero strain stretchlaminate web to impart elasticity thereto” to Weber et al on Dec. 1,1992. The depth of engagement of the ring-roll may be varied along thelongitudinal axis 1000 of the backsheet 126 in order to produce thediffering first and second backsheet zones.

The above-mentioned method of stretching the backsheet material may beachieved by any suitable technique including, but not limited to, usingpitched or non-pitched ring rolls having mating and interpenetratingteeth. In either case, the teeth may engage the material at differentdepths of engagement along the width and/or length of the material toprovide different zones of stretch. Typically, said engagement impartsan applied strain between 0% and 200% to the material.

In the case of pitched activation, for example, the changing depth ofengagement may be accomplished by having the mating rolls machined todifferent circumferences such that their teeth engage at differentdepths. In the case of non-pitched activation, for example, the rollsmay be made to matching concentric diameters but their center-to-centerdistance may be changed to alter their depth of engagement. Forinstance, an upper roll may be driven downward to engage a lower roll,but the upper roll may be raised (e.g., by a cam against roll shaft) ina periodic manner to alter the depth of engagement.

When stretching the material, holes in said material are oftenundesirable. One known technique for minimizing the number of unwantedholes is to control the strain rate (e.g., less than 800 sec−1, morepreferably less than 300 sec−1). The strain rate may be controlled bycontrolling roll speed and diameter. Additionally, holes may result whenadhesive is applied in an area that spans two or more adjacentactivation teeth. More specifically, the adhesive may be strained tofailure, thus resulting in a high strain rate release that causes holesin the adjacent material. One known technique to minimize adhesivefailure is to apply said adhesive in a discontinuous fashion such thatit does not span two or more adjacent activation teeth. Another knowntechnique is to apply heat (e.g., above 40 degrees Celsius, or morepreferably above 50 degrees Celsius) to said adhesive prior to or duringthe stretch process to cause it to be more fluid and less brittle.

Regardless of the stretching method employed, incorporating differingbacksheet zones allows for various shaping of the absorbent article 120in light of the varying three-dimensional nature of the wearer'sanatomy. For example, second backsheet zone 170 is more conformableabout the wearer because of its lower value of one of said physicalproperties. Furthermore, second backsheet zone 170 provides bettercoverage of the wearer's anatomy in its stretched state. Consequently,second backsheet zone is better suited to conform about the wearer, forexample, the buttocks region 39 where the wearer's body protrudes themost. Conversely, first backsheet zone 160 need not be as conformable inorder to adapt to the wearer in the crotch region 37 and front waistregion 36.

In certain preferred embodiments, the second backsheet zone overlaps theback portion of the absorbent core. In these embodiments, the portion ofthe second backsheet zone overlapping the core is preferably either notbonded to the core or is bonded only in a narrow region along thelongitudinal axis of the article. The area of bonding between theabsorbent core and the second backsheet zone is preferably less thanhalf the area of overlap. In other preferred embodiments, the secondbacksheet zone does not extend completely to the back lateral edge ofthe article (i.e., the total pathlength of the backsheet at the backlateral edge of the article is less than the total pathlength of thebacksheet in the second backsheet zone).

Additionally, in accordance with the present invention, an elastomericelement 190 may be applied to backsheet 126 to provide sustained fit andconformity to the wearer's body. Elastomeric element 190 may be joinedto backsheet 126 in an area at least partially overlapping the secondbacksheet zone 170 and preferably overlapping the longitudinal axis ofthe article. Preferably, the relaxed pathlength of elastomeric element190 is shorter than the total pathlength of backsheet 126 within thesecond backsheet zone 170 in their area of joining. For example, theratio of the relaxed pathlength of elastomeric element 190 to the totalpathlength of backsheet 126 within the second backsheet zone 170 in thejoined area is less than about 0.8, more preferably less than about 0.7,and most preferably less than about 0.6. Importantly, the differencebetween these pathlengths defines the maximum elongation of the stretchzone. The elastomeric element may be elongated up to the totalpathlength of the backsheet in the stretch zone area with only minimalresistance from the backsheet. However, once the elastomeric element iselongated to the total backsheet pathlength, significant resistance tofurther elongation is provided by the backsheet material (i.e., thebacksheet acts to provide a “force wall” to prevent further significantelongation under the forces normally encountered in a wearable absorbentarticle). Additionally, the pathlength of the topsheet 24 may be shorterthan the pathlength of the backsheet 126 to provide an additional forcewall. This phenomenon is important to prevent sagging of the articleonce loaded by the wearer's waste or stressed by the wearer's physicalactivity. Additionally, in preferred embodiments, the force to elongatethe stretch zone a given proportion is less than the force required toelongate one of the stretch ears or side panels proportionately.

Elastomeric element 190 may be bonded in an unstretched state tobacksheet 126 in the desired backsheet zone prior to the stretching(e.g., ring-rolling) process. Elastomeric element 190 may be strained toapproximately the same degree as backsheet 126 within the backsheetzone, in their area of overlap, during the stretching process. However,upon release of the straining tension, elastomeric element 190 relaxesto a smaller pathlength than that of backsheet 126 in the stretched area(i.e., the elastomeric element 190 recovers a greater percentage of theapplied strain). Alternatively, elastomeric element 190 may be affixedto backsheet 126 or the topsheet in a pre-stretched condition eitherprior to, or subsequent to, the aforementioned stretching step. Suitableelastomeric elements include, but are not limited to, films, aperturedfilms, strands, extruded strands, extruded elastomers, slot coatedelastomeric adhesives, printed elastomers, scrims, foams, elasticnonwovens, and SELFed materials (as exampled in U.S. Pat. No. 5,916,663,supra). In preferred embodiments, the elastomeric element 190 isoriented in substantially the lateral direction and the backsheetstretching process extends the backsheet 126 in substantially the samedirection, thus resulting in a primary stretch vector 173 of the stretchzone 172 oriented around the back waist of the wearer.

Where a backsheet zone (e.g., second backsheet zone 170) and anelastomeric element (e.g., elastomeric element 190) overlap, a stretchzone 172 is created. More specifically, for example, elastomeric element190 is joined to an at least partially overlapping area of secondbacksheet zone 170 to form stretch zone 172. Thus, stretch zone 172provides the combined functions of improved coverage, sustained fit andconformity to the varying three-dimensional geometries of the wearer'sbody. Stretch zone 172 may be characterized by measuring the relaxedpathlength of its elastomeric element 190 and by measuring the totalpathlength of its second backsheet zone 170 as described above.

Typically, stretch zones have the following properties: (1) an elasticresistive force (i.e., a normalized load at 25% elongation) of at leastabout 0.03 N/cm, preferably from 0.03 N/cm to about 50 N/cm, morepreferably from about 0.05 N/cm to about 40 N/cm, and most preferablyfrom 0.25 n/cm to about 30 N/cm; 2) a percent set of less than about25%, preferably less than about 15% and more preferably less than about10%; and (3) a stress relaxation value of less than about 50%,preferably less than about 30%, and more preferably less than about 20%.Methods for measuring these properties are given in U.S. patentapplication Ser. No. 10/288095, filed on Nov. 5, 2002 and published asUS 2003/0088228A1.

Each stretch zone may have continuous or discontinuous properties in anydirection wherein the varying properties include chemical composition,elasticity, extensibility, maximum elongation, other stress/strainproperties, vectors or angles, basis weight, geometry, dimensions,3-dimensional morphology, visual distinctiveness, and the like. Astretch zone may have continuous properties (e.g., elastomericcomposition, substrate material and/or treatment have relativelyhomogeneous properties). Alternatively, stretch zones may havediscontinuous properties due to provision of non-homogeneous propertiesthereto. In certain embodiments, at least a portion of at least onestretch zone may be visually distinct. In certain preferred embodiments,the stretch zone at least partially overlaps the region between the rearfasteners of the article so as to store elastic energy in a continuousline of tension to enhance the conformity and sustained fit of thearticle.

FIG. 3 is a plan view of another exemplary, non-limiting embodiment of adiaper 220 of the present invention in its flat-out, uncontracted state(i.e., without elastic induced contraction) with the backsheet 226,which contacts the wearer's garment, shown facing the viewer. Similar toFIG. 2, diaper 220 has a first backsheet zone 260 and a second backsheetzone 270. Additionally, diaper 220 has a third backsheet zone 280. Firstbacksheet zone 260 is disposed primarily in the crotch region 237 andfront waist region 236. Second backsheet zone 270 is disposed primarilyin the distal portion of back waist region 238. Third backsheet zone 280is disposed longitudinally inboard of the second backsheet zone 270(e.g., primarily in the buttocks region 239). Third backsheet zone 280has a lower basis weight, thickness, or density than second backsheetzone 270 which has a lower basis weight, thickness, or density thanfirst backsheet zone 260. Third backsheet zone 280 is designed toconform to the outward-protruding buttocks of the wearer. Diaper 220also has an elastomeric element 290 which overlaps a portion of secondbacksheet zone 270 and is joined to the diaper in the overlapping, thusforming a stretch zone 272 having a primary direction of stretch in thelateral direction as indicated by arrow 273. Stretch zone 272 may becharacterized by measuring the relaxed path length of its elastomericelement 290 and by measuring the total pathlength of its secondbacksheet zone 270 as described herein. Stretch zone 272 (i.e., secondbacksheet zone 270 combined with elastomeric element 290) is locatednear the distal portion of back waist region 238 so as to anchor thediaper 220 to the lower back region of the wearer, discussed infra. Asexampled in this embodiment, not all backsheet zones (herein thirdbacksheet zone 280) overlap an elastomeric element. While thirdbacksheet zone 280 does not provide elastic recovery to the diaper 220,it may function to cover and conform to the wearer's anatomy and to beartensions or loads associated with the anatomy or motion of the wearer,or the diaper or contents thereof, e.g., through the waist or buttocksregion of the article, especially in regions where they are not affixedto the absorbent core (not shown) or other thicker, more rigid elementsof the diaper. As exampled, these zones may be discrete zones havingdifferent properties than the backsheet zone(s) comprising the stretchzone(s). Alternatively, these zones may comprise the portions of any ofthe backsheet zones not joined to an elastomeric element. Lastly, in anon-limiting example, the absorbent core (not shown) is either affixedto backsheet 226 in the third backsheet zone 280 along longitudinalcenterline 1000 or not at all in the region where the backsheet zoneoverlaps the absorbent core. In another non-limiting example, theabsorbent core (not shown) does not extend into the second backsheetzone 270.

FIG. 4 is a plan view of yet another exemplary, non-limiting embodimentof a diaper 320 of the present invention in its flat-out, uncontractedstate (i.e., without elastic induced contraction) with the backsheet326, which contacts the wearer's garment, shown facing the viewer.Similar to FIG. 3, diaper 320 has a first backsheet zone 360, a secondbacksheet zone 370 and a third backsheet zone 380. First backsheet zone360 is disposed primarily in the crotch region 337 and front waistregion 336. Second backsheet zone 370 is disposed primarily in thedistal portion of back waist region 338. Third backsheet zone 380 isdisposed primarily in the back waist region 338 with at least a portionextending into buttocks region 339. Third backsheet zone 380 has a lowerbasis weight, thickness, or density than second backsheet zone 370 whichhas a lower basis weight, thickness, or density than first backsheetzone 360. Third backsheet zone 380 is such designed to conform to theoutward-protruding buttocks of the wearer. Diaper 320 also has anelastomeric element 390 which overlaps and is joined to a portion ofsecond backsheet zone 370 and third backsheet zone 380, thus forming twodiscrete stretch zones 372, 382 having a primary direction of stretch inthe lateral direction as indicated by arrow 373. In this way, only asingle elastomeric element 390 is needed to create a first stretch zone372 and a second stretch zone 382. Stretch zone 372 (i.e., secondbacksheet zone 370 combined with elastomeric element 390) is locatednear the distal portion of back waist region 338 so as to anchor thediaper 320 to the lower backside of the wearer, discussed infra. Stretchzone 382 (i.e., third backsheet zone 370 combined with elastomericelement 390) is located longitudinally inboard of stretch zone 372 andsubstantially, laterally-aligned with fastening elements 355. Being moreextensible than stretch zone 372, stretch zone 382 facilitates thelateral pulling of fastening elements 355 by the wearer or caregiverparticularly during application and the generation of a line of tensionbetween the fastening elements; whereas, stretch zone 372 continues toprovide anchoring within the back waist region 338 and prevents gappingat the back waist edge. In a non-limiting example, the absorbent core(not shown) is either affixed to backsheet 326 in the third backsheetzone 380 along longitudinal centerline 1000 or not at all. In anothernon-limiting example, the absorbent core (not shown) does not extendinto the second backsheet zone 370.

FIG. 5 is a plan view of yet another exemplary, non-limiting embodimentof a diaper 420 of the present invention in its flat-out, uncontractedstate (i.e., without elastic induced contraction) with the backsheet426, which contacts the wearer's garment, shown facing the viewer.Similar to FIG. 3, diaper 420 has a first backsheet zone 460, a secondbacksheet zone 470 and a third backsheet zone 480. First backsheet zone460 is disposed primarily in the crotch region 437 and front waistregion 436. Second backsheet zone 470 is disposed primarily in thedistal portion of back waist region 438. Third backsheet zone 480 isdisposed primarily in the back waist region 438 with at least a portionextending into buttocks region 439. Third backsheet zone 480 has a lowerbasis weight, thickness, or density than second backsheet zone 470 whichhas a lower basis weight, thickness, or density than first backsheetzone 460. Third backsheet zone 480 is such designed to conform to theoutward-protruding buttocks of the wearer. Diaper 420 also has a firstelastomeric element 490 which overlaps and is joined to a portion ofsecond backsheet zone 470, thus forming a first stretch zone 472 havinga primary direction of stretch in the lateral direction as indicated byarrow 473. Additionally, diaper 420 has a second elastomeric element 493which overlaps and is joined to a portion of third backsheet zone 480,thus forming a second stretch zone 482 having a primary direction ofstretch in a non-linear (e.g., substantially u-shaped) configuration asindicated by arrow 483. In this way, two elastomeric elements 490, 493are used to create a first stretch zone 472 and a second stretch zone482, respectively. Stretch zone 472 (i.e., second backsheet zone 470combined with elastomeric element 490) is located near the distalportion of back waist region 438 so as to anchor the diaper 420 to thelower backside of the wearer, discussed infra. Stretch zone 482 (i.e.,third backsheet zone 470 combined with elastomeric element 490) islocated longitudinally inboard of stretch zone 472 so as to providecontoured stretch within the buttocks region 439. In a non-limitingexample, the absorbent core (not shown) is either affixed to backsheet426 in the third backsheet zone 480 along longitudinal centerline 1000or not at all. In another non-limiting example, the absorbent core (notshown) does not extend into the second backsheet zone 470.

FIG. 6 is a plan view of yet another exemplary, non-limiting embodimentof a diaper 520 of the present invention in its flat-out, uncontractedstate (i.e., without elastic induced contraction) with the backsheet526, which contacts the wearer's garment, shown facing the viewer.Similar to FIG. 3, diaper 520 has a first backsheet zone 560, secondbacksheet zone 570 and a third backsheet zone 580. First backsheet zone560 is disposed primarily in the crotch region 537 and front waistregion 536. Second backsheet zone 570 is disposed primarily in the backwaist region 538. Third backsheet zone 580 is disposed primarily in thefront waist region 536. Third backsheet zone 580 has a lower basisweight, thickness, or density than second backsheet zone 570 which has alower basis weight, thickness, or density than first backsheet zone 560.Diaper 520 also has an elastomeric element 590 which overlaps and isjoined to a portion of third backsheet zone 580, thus forming stretchzone 582 having a primary direction of stretch in the longitudinaldirection as indicated by arrow 583. In this embodiment, one skilled inthe art would recognize the desirability to stretch the backsheet in thelongitudinal direction and that the pathlengths of the backsheet zone580 and elastomeric element 590 should be measured in the longitudinaldirection as well. Stretch zone 582 (i.e., third backsheet zone 580combined with elastomeric element 590) is located in the front waistregion 536 so as to facilitate the variable stretch during applicationof diaper 520 given the varying lengths of wearers' torsos. In anon-limiting example, the absorbent core (not shown) does not extendinto the second backsheet zone 570. In a non-limiting example, theabsorbent core (not shown) is not attached to the backsheet 526 instretch zone 582. One skilled in the art should appreciate thisparticular embodiment may be practiced without the presence of thesecond backsheet zone 570 in the back waist region 560.

FIG. 7 is a plan view of yet another exemplary, non-limiting embodimentof a diaper 620 of the present invention in its flat-out, uncontractedstate (i.e., without elastic induced contraction) with the backsheet626, which contacts the wearer's garment, shown facing the viewer.Similar to FIG. 3, diaper 620 has a first backsheet zone 660, a secondbacksheet zone 670 and a third backsheet zone 680. First backsheet zone660 is disposed primarily in the crotch region 637 and front waistregion 636. Second backsheet zone 670 is disposed primarily in thedistal portion of back waist region 638. Third backsheet zone 680 isdisposed primarily in the back waist region 638 with at least a portionextending into buttocks region 639. Third backsheet zone 680 has a lowerbasis weight, thickness, or density than second backsheet zone 670 whichhas a lower basis weight, thickness, or density than first backsheetzone 660. Third backsheet zone 680 is such designed to conform to theoutward-protruding buttocks of the wearer. Diaper 620 also has anelastomeric element 690 which overlaps and is joined to a portion ofsecond backsheet zone 670, thus forming discrete stretch zones 672having a primary direction of stretch in the lateral direction asindicated by arrow 673. Stretch zone 672 (i.e., second backsheet zone670 combined with elastomeric element 690) is located near the distalportion of back waist region 638 so as to anchor the diaper 620 to thelower backside of the wearer, discussed infra.

Stretch zone 672 may be preferably aligned with the ears 697 and/orfasteners 655 disposed on ears 697 in order to create a substantiallycontinuous line of tension around the waist to promote conformingsustained fit. As shown in FIG. 7, stretch zone 672 preferably at leastpartially overlaps one of the two imaginary lines 656 a and 656 b thatconnect the longitudinally outboard edges 655 a and 655 b of eitherfasteners 655. In embodiments in which diaper 620 does not includefasteners 655, for example in diaper pant 720 of FIG. 8, imaginary lines656 a and 656 b may connect the narrowest outboard point edges 697 a and697 b of ears 697. In some embodiments, a stiffening member may be usedto further distribute the elongation force throughout the ears 697. Insuch embodiments which include a stiffening element that is wider thanthe fastener (not shown), the separation of the imaginary lines isdefined by the longitudinal length of the stiffening element.

In a non-limiting example, the absorbent core (not shown) is eitheraffixed to backsheet 626 in the third backsheet zone 680 alonglongitudinal centerline 1000 or not at all. In another non-limitingexample, the absorbent core (not shown) does not extend into the secondbacksheet zone 670.

FIG. 8 is a plan view of an exemplary, non-limiting embodiment of a pant720 of the present invention in its flat-out, uncontracted,non-preformed state (i.e., without elastic induced contraction) withportions of the structure being cut away to more clearly show theunderlying structure of the diaper 720 and with the portion of thediaper 720 which contacts the wearer shown facing the viewer. The diaper720 includes a longitudinal axis 1000 and a lateral axis 1100. One endportion 736 of the diaper 720 is configured as a front waist region 736of the diaper 720. The opposite end portion 738 is configured as a backwaist region 738 of the diaper 720. An intermediate portion 737 of thediaper 720 is configured as a crotch region 737, which extendslongitudinally between the front and back waist regions 736 and 738. Thewaist regions 736 and 738 generally comprise those portions of thediaper 720 which, when worn, encircle the waist of the wearer. The waistregions 736 and 738 may include elastic elements such that they gatherabout the waist of the wearer to provide improved fit and containment.The crotch region 737 is that portion of the diaper 720 which, when thediaper 720 is worn, is generally positioned between the legs of thewearer. Another intermediate portion 739 of the diaper 720 is configuredas a buttocks region, which is located in or near the proximal end ofback waist region 738. The outer periphery of diaper 720 is defined bylongitudinal edges 714 and end edges 710, 712 which are located alongthe front and back waist region 736, 738, respectively. First connectionzones 757 a, 757 b are attached to second connection zones 759 a, 759 b,respectively, prior to being purchased by the consumer (e.g., prior tobeing packaged) as exampled in FIG. 8. Diaper 720 is preferably appliedto a wearer by inserting the wearer's legs through the leg openings andthen diaper 720 is pulled up over the wearer's buttocks.

It is herein contemplated and should be appreciated by one skilled inthe art that the present invention may be applied to a pant (e.g., FIG.8) and a non-preformed (e.g., FIG. 1) absorbent article. As such, all ofthe herein disclosed and foreseeable embodiments apply to both pant andnon-preformed absorbent articles.

FIG. 9 is a plan view of the exemplary, non-limiting embodiment diaper620 from FIG. 7. FIG. 10 a is a schematic, cross-sectional view ofdiaper 620 from FIG. 9 being worn as illustrated along line 10-10 inFIG. 11. For purposes of FIG. 10 a, diaper 620 is illustrated as adiaper having a front-fastened product execution which may or may not bepreformed. Ears 697 are shown having stretch properties in the lateraldirection as indicated by arrows 698. It has been discovered that diaper620 provides better conformity and sustained fit when a first stretchregion (e.g., second backsheet zone 670) having lateral stretch asindicated by vector 673 co-elongates with a second stretch region (e.g.,ears 697) having lateral stretch as indicated by vector 698 under thesame tensile force. In this way, the first stretch region (e.g., secondbacksheet zone 670) stretches and conforms to the wearer before thesecond stretch region (e.g., ears 697) is substantially stretched (i.e.,stretched near its limit—that is, stretched near its maximumelongation); otherwise, the first region may wrinkle, gap, and/or beginto sag. In practical terms, when the caregiver applies diaper 620 with agiven application tension, the first stretch region should co-elongatewith the second stretch region instead of only beginning to elongatewhen the second stretch region is stretched near its limit. In preferredexecutions, under a laterally applied tensile load of between about 1Newton and about 4 Newtons, the strain in the second stretch region isbetween at least about 10% and less than about 75%. Under the sametensile load, the strain the first stretch region is preferably greaterthan about 5%, more preferably greater than about 10%, and mostpreferably at least about equal to the strain in the second stretchregion. The co-elongation exhibited between the first and second regionsmay be imparted through a variety of product designconfigurations/techniques including, but not limited to, (a) varying thelongitudinal length and/or lateral width of the first and/or secondstretch zone [e.g., longitudinally taller ears/side panels compared to alongitudinally shorter backsheet zone/stretch zone] and (b) varying thetensile modulus of the first and/or second stretch zone [e.g., thetensile modulus for the backsheet zone/stretch zone may be lower thanthe tensile modulus for the ears/side panels].

Similar to FIG. 10 a, FIG. 10 b shows a diaper having a side-fastenedproduct execution which may or may not be preformed, wherein, a firststretch region (e.g., second backsheet zone 770) having lateral stretchas indicated by vector 773 co-elongates with a second stretch region(e.g., side panels 797) having lateral stretch 798 under the sametensile force. While the term “ears” is used herein when referring tonon-pant diapers and the term “side panels” is used herein whenreferring to pant diapers, the two terms may be used hereininterchangeably when appreciating the present invention.

FIG. 11 is a side elevational view of the exemplary, non-limitingembodiment diaper 120 from FIG. 2 being worn by a wearer 900. Assimilarly illustrated in FIG. 2, backsheet 126, first backsheet zone160, second backsheet zone 170, elastomeric element 190, stretch zone172 and fastening element 155 are shown. FIG. 12 is a schematic, sideelevational view of diaper 120 from FIG. 11. Referring now to both FIGS.11 and 12, stretch zone 172 may be located at the back waist end 136 ofdiaper 120, located generally in the lower back waist area 910. In thisway, the maximum fit and comfort will be experienced by wearer 900 asthe tension is applied by diaper 120 to the wearer's body at orimmediately above the convexity of the buttocks 920 (i.e., the buttocks“shelf”), contributing to the overall anchoring capability of diaper 120(i.e., its ability to resist sagging). Said another way, stretch zone172 operates to maintain diaper 120 in an optimal fit configuration withrespect to the low motion zone 930 (i.e. the line or zone connecting thelumbar curve of the back over the hips to under the abdominal crease ofa wearer's body 900) so as to maximize the performance thereof. For amore detailed discussion of low motion zones see U.S. Pat. No.5,358,500.

TEST METHOD FOR MEASURING ELONGATION FORCE

-   -   1. Connect fastener components on one side of article (e.g., 759        a and 757 a in FIG. 10 a). If article is a preformed pant, then        break a connection on one side of article prior to testing.    -   2. Cut article along lateral axis 1100.    -   3. Make a pair of tick marks (i.e., indicia) within both the        first stretch region and second stretch region. Measure the        lateral gap for each pair of tick marks.    -   4. Grip opposing unconnected ends/fastening components in jaws        at least as wide as the material being clamped. Grips should be        attached such that a lateral tensile force can be applied to the        first and second stretch regions between the jaws.    -   5. For a first test iteration, apply a 1 Newton tensile force,        and then within about 15 seconds of applying said tensile force,        measure the lateral gap for each pair of tick marks while the        article is held in jaws.    -   6. For a second test iteration, apply a total of 2 Newton        tensile force, and then within about 15 seconds of applying said        tensile force, measure the lateral gap for each pair of tick        marks while the article is held in jaws.    -   7. For a third test iteration, apply a total of 4 Newton tensile        force, and then within about 15 seconds of applying said tensile        force, measure the lateral gap for each pair of tick marks while        the article is held in jaws.    -   8. Calculate Strain=[100*(Distance_((final))−Distance        _((initial)))/Distance_((initial))] for first and second stretch        regions for each test iteration.    -   9. Compare the strains of the first and second stretch regions.        The following relationship should be true for at least one of        the three test iterations:        -   The first stretch region is said to co-elongate with the            second stretch region when: (a) the strain in the second            stretch region is between at least about 10% and less than            about 75% and (b) the strain the first stretch region is            preferably greater than about 5%, more preferably greater            than about 10%, and most preferably at least about equal to            the strain in the second stretch region.

The second region may be extensible or more preferably elastomeric. Thesecond region may be located in any portion of the front waist region636 or back waist region 638 including, but not limited to, a locationnear longitudinal centerline 1000 of said front waist region 636,laterally outboard from longitudinal centerline 1000 near one or bothlongitudinal edges 614 in either waist region, or in side panels 697attached to one or more longitudinal edge 614 in one or more waistregions.

All documents cited are, in relevant part, incorporated herein byreference; the citation of any document is not to be construed as anadmission that it is prior art with respect to the present invention.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

For example, one skilled in the art should appreciate that the presentinvention may also be incorporated into other wearable absorbentarticles, such as catamenial and adult incontinence products, thatencircle or enclose at least a portion of a wearer's anatomy or whichare otherwise secured to a wearer.

One skilled in the art should also appreciate that the stretch zones maybe parallel or nonparallel with respect to the lateral or longitudinalcenterlines or with respect to each other. Additionally, the stretchzones may have different physical and/or elastic properties versus eachother.

One skilled in the art should also appreciate that the elastomericelements may be configured in any suitable shape including, but notlimited to, linear and non-linear (e.g., substantially u-shaped, etc.).

While exemplary embodiments disclosed herein depicted the thirdbacksheet zone having a lower basis weight, thickness, or density thanthe second backsheet zone which has a lower basis weight, thickness, ordensity than the first backsheet zone, one skilled in the art shouldalso appreciate that second backsheet zone and/or first backsheet zonemay have a lower physical property value than the third backsheet zonein some applications. For example, referring to FIG. 3, the secondbacksheet zone 270 (disposed primarily in the distal portion of the backwaist region 238) may have a lower basis weight, thickness or densitythan that of the third backsheet zone 280 (disposed primarily in thebuttock region 239). In this way, second backsheet zone 270 providesgreater breathability (i.e., increased air permeability) than thirdbacksheet zone 280 thus providing better dryness and comfort in thewearer's waist region; whereas, the third backsheet zone 280 is moreadapted to ensure sufficient exudate containment. In another example,third backsheet zone 280 may have a lower basis weight, thickness ordensity than that of the second backsheet 270 in order to providesufficient extension to enable pull-on application of the article (e.g.,for pants).

While exemplary embodiments disclosed herein depict the second backsheetzone, for example, being positioned slightly away from the end edge 12so as to provide less stretch for maintaining fit and shape, one skilledin the art would recognize that this gap (i.e., positioning away) mayvary in length, including not existing.

While the physical properties of basis weight, thickness and density arediscussed herein as methods for appreciating and measuring the presentinvention, one skilled in the art would recognize that tensile modulusmay also sometimes be an acceptable physical property that may bemeasured to appreciate the present invention. Tensile modulusdifferences may be preferably measured with the backsheet strain between0% and 5% elongation of the backsheet, or alternatively between 0% to25%, or alternatively between 0% to 50%.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, including any cross referenced or relatedpatent or application, is hereby incorporated herein by reference in itsentirety unless expressly excluded or otherwise limited. The citation ofany document is not an admission that it is prior art with respect toany invention disclosed or claimed herein or that it alone, or in anycombination with any other reference or references, teaches, suggests ordiscloses any such invention. Further, to the extent that any meaning ordefinition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A disposable wearable absorbent article,comprising: a front waist region; a back waist region; a crotch regiondisposed between the front waist region and the back waist region; alongitudinal axis; a lateral axis that is perpendicular to thelongitudinal axis; a topsheet; and a backsheet comprising a firstbacksheet zone and a second backsheet zone; wherein the first backsheetzone overlaps the longitudinal axis and comprises a physical property oftensile modulus; wherein the second backsheet zone overlaps thelongitudinal axis and does not overlap the lateral axis, wherein a firstportion of the second backsheet zone extends laterally outwardly from afirst side of the longitudinal axis, wherein a second portion of thesecond backsheet zone extends laterally outwardly from a second side ofthe longitudinal axis, and wherein the second backsheet zone comprisesthe physical property; wherein the physical property of the firstbacksheet zone and the physical property of the second backsheet zoneare different: wherein the first backsheet zone is disposed at leastpartially in the front waist region; and wherein the second backsheetzone is disposed at least partially in the back waist region.
 2. Thedisposable wearable absorbent article of claim 1, wherein the physicalproperty of the first backsheet zone has a first value, wherein thephysical property of the second backsheet zone has a second value, andwherein the second value is less than the first value.
 3. The disposablewearable absorbent article of claim 1, wherein the second backsheet zoneis disposed in a laterally central portion of the article.
 4. Thedisposable wearable absorbent article of claim 1, wherein the firstbacksheet zone is disposed at least partially in the crotch region. 5.The disposable wearable absorbent article of claim 1, wherein the firstbacksheet zone is disposed at least partially in the back waist region.6. The disposable wearable absorbent article of claim 1 , comprising anabsorbent core, wherein the second backsheet zone at least partiallyoverlaps the absorbent core.
 7. The disposable wearable absorbentarticle of claim 1, wherein the second backsheet zone is disposed atleast partially in the crotch region.
 8. The disposable wearableabsorbent article of claim 1, wherein the back waist region comprises abuttocks region disposed at a proximal end of the back waist region, andwherein the second backsheet zone is disposed at least partially in thebuttocks region.
 9. The disposable wearable absorbent article of claim1, wherein the back waist region comprises a buttocks region disposed ata proximal end of the back waist region, and wherein the secondbacksheet zone is disposed outside of the buttocks region.
 10. Thedisposable wearable absorbent article of claim 1, configured to befront-fastening or side-fastening.
 11. The disposable wearable absorbentarticle of claim 1, configured to be non-refastenable.
 12. A disposablewearable absorbent article, comprising: a longitudinal axis; a lateralaxis that is perpendicular to the longitudinal axis; a front waistregion; a back waist region; a topsheet; and a backsheet comprising afirst backsheet zone and a second backsheet zone, wherein the firstbacksheet zone is at least partially positioned in the front waistregion, wherein the second backsheet zone is positioned in the backwaist region, wherein an area of the first backsheet zone positioned inthe back waist region is positioned intermediate an outboard edge of theabsorbent article and a portion of the second backsheet zone; whereinthe area of the first backsheet zone comprises a physical property ofbasis weight, thickness, tensile modulus, or density; wherein the secondbacksheet zone overlaps the longitudinal axis, wherein the secondbacksheet zone is disposed in a laterally central portion of the secondportion, and wherein the second backsheet zone comprises the physicalproperty; and wherein the physical property of the area of the firstbacksheet zone and the physical property of the second backsheet zoneare different.
 13. The disposable wearable absorbent article of claim12, wherein the second backsheet zone extends laterally outwardly from afirst side of the longitudinal axis and extends laterally outwardly froma second side of the longitudinal axis.
 14. The disposable wearableabsorbent article of claim 12, wherein the area is locatedlongitudinally inboard of a fastener in the back waist region.
 15. Thedisposable wearable absorbent article of claim 12, wherein the area islocated intermediate a fastener in the back waist region and the lateralaxis.
 16. The disposable wearable absorbent article of claim 12, whereinthe first backsheet zone comprises a second area in the back waistregion, wherein the second area is positioned intermediate a secondoutboard edge, opposing the outboard edge, of the absorbent article anda second portion of the second backsheet zone, wherein the second areacomprises the physical property, and wherein the physical property ofthe second area and the physical property of the second backsheet zoneare different.
 17. The disposable wearable absorbent article of claim16, wherein the physical property of the area and the physical propertyof the second area are substantially the same or the same.
 18. Thedisposable wearable absorbent article of claim 12, wherein the physicalproperty of the area of the first backsheet zone has a first value,wherein the physical property of the second backsheet zone has a secondvalue, and wherein the second value is less than the first value. 19.The disposable wearable absorbent article of claim 12, wherein thebacksheet comprises a nonwoven material.
 20. A disposable wearableabsorbent article, comprising: a longitudinal axis; a lateral axis thatis perpendicular to the longitudinal axis; a front waist region; a backwaist region; a crotch region disposed between the front waist regionand the back waist region; a topsheet; and a backsheet comprising afirst backsheet zone and a second backsheet zone, wherein the firstbacksheet zone is at least partially positioned in the back waistregion, wherein the second backsheet zone is at least partiallypositioned in the back waist region, wherein an area of the firstbacksheet zone positioned in the back waist region is positionedintermediate an outboard edge of the absorbent article and a portion ofthe second backsheet zone; wherein the area of the first backsheet zonecomprises a physical property of basis weight, thickness, tensilemodulus, or density; wherein the second backsheet zone overlaps thelongitudinal axis, and wherein the second backsheet zone comprises thephysical property; and wherein the physical property of the area of thefirst backsheet zone has a first value, wherein the physical property ofthe second backsheet zone has a second value, and wherein the firstvalue is greater than the second value.
 21. The disposable wearableabsorbent article of claim 20, wherein the area has a lateral widthsmaller than a lateral width of the second backsheet zone.
 22. Thedisposable wearable absorbent article of claim 20, wherein the backsheetcomprises a nonwoven material.
 23. The disposable wearable absorbentarticle of claim 20, wherein the backsheet comprises a liquidimpermeable material.
 24. A disposable wearable absorbent article,comprising: a longitudinal axis; a lateral axis that is perpendicular tothe longitudinal axis; a front waist region on a first side of thelateral axis; a back waist region on a second side of the lateral axis;a topsheet; and a backsheet comprising a first backsheet zone and asecond backsheet zone, wherein the first backsheet zone is at leastpartially positioned in the back waist region, wherein the secondbacksheet zone is positioned in the back waist region, wherein an areaof the first backsheet zone positioned in the back waist region ispositioned intermediate an outboard edge of the absorbent article and aportion of the second backsheet zone; wherein the area of the firstbacksheet zone comprises a physical property of basis weight, thickness,tensile modulus, or density; wherein the second backsheet zone comprisesthe physical property; and wherein the physical property of the area ofthe first backsheet zone has a first value, wherein the physicalproperty of the second backsheet zone has a second value, and whereinthe first value is greater than the second value.